mabshoff wrote:
>
>
> On Oct 24, 6:27 pm, "William Stein" <[EMAIL PROTECTED]> wrote:
>> On 10/24/07, Jaap Spies <[EMAIL PROTECTED]> wrote:
>
> I am on that, I got a 32 bit build of 2.8.9.alpha0.
>> By the way, could you remind me where dance is defined?
>>
>> sage: search_src('dance')
>> [nothing]
>> sage:
>>
>>
It is not in matrix2.pyx, It is on the bottom of my first message and heer
below.
It uses some functions/methods present in matrix2.pyx:
rook_vector, permanental_minor, prod_of_row_sums, permanent.
>>>> increase the amount of swap you have in that box. Adding more physical
>>>> RAM will probably makes the problem go away, too.
>>> I rebooted with no succes. Same error using 50-60% of 1 GB memory.
>>> Swap space is 5 GB.
>>> Jaap
>
> Ok, I will investigate on a 32 bit box then. Could you give us
> distribution/gcc and so on please? It might be related to specific
> compilers.
>
Linux paix 2.6.22.9-91.fc7 #1 SMP Thu Sep 27 23:10:59 EDT 2007 i686 i686 i386
GNU/Linux
gcc (GCC) 4.1.2 20070925 (Red Hat 4.1.2-27)
Jaap
-------
##########################################################################
# Copyright (C) 2006 Jaap Spies, [EMAIL PROTECTED]
#
# Distributed under the terms of the GNU General Public License (GPL):
#
# http://www.gnu.org/licenses/
##########################################################################
"""
Usage from sage
sage: attach 'dancing.sage'
sage: dance(4)
h^4 - 2*h^3 + 9*h^2 - 8*h + 6
"""
# use variable 'h' in the polynomial ring over the rationals
h = QQ['h'].gen()
def dance(m):
"""
Generates the polynomial solutions of the Dancing School Problem
Based on a modification of theorem 7.2.1 from Brualdi and Ryser,
Combinatorial Matrix Theory.
See NAW 5/7 nr. 4 december 2006 p. 285
INPUT: integer m
OUTPUT: polynomial in 'h'
EXAMPLE:
sage: dance(4)
h^4 - 2*h^3 + 9*h^2 - 8*h + 6
AUTHOR: Jaap Spies (2006)
"""
n = 2*m-2
M = MatrixSpace(ZZ, m, n)
A = M([0 for i in range(m*n)])
for i in range(m):
for j in range(n):
if i > j or j > i + n - m:
A[i,j] = 1
rv = A.rook_vector()
# print rv
s = sum([(-1)^k*rv[k]*falling_factorial(m+h-k, m-k) for k in range(m+1)])
print s
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